1. Field of the Invention
The present invention relates to an outer lead bonding apparatus and, more particularly, to an apparatus for bonding various kinds of devices punched from film carriers to substrates accurately and easily.
2. Description of the Prior Art
An outer lead bonding apparatus is known in the art which bonds outer leads of devices punched from film carriers to frame or substrate (hereinafter referred to as substrate) by aligning the terminals of the outer leads to the electrodes of the substrate. A typical example of the apparatus is disclosed in Japanese Laid-Open Patent Publication (Kokai) No. 63-20846.
The known outer lead bonding apparatus includes film carrier supply reels, and spacer tape wind-up reels within the body. While a film carrier is being drawn from each supply reel, desired devices having outer leads are punched from the film carrier by means of a cutting tool such as a punch, and the devices are then conveyed by a suction or vacuum head to a place where they are Joined to substrates.
The known prior art apparatus has the following disadvantages:
(i) The devices punched from the film carrier are transferred to the substrate by means of a single suction means, which takes them up and allows a camera to monitor them for alignment. Then the suction head transfers the devices to the substrates and mounts them thereon. Finally, the suction head returns to a place where it recycles to pick up new devices. The series of operations require a relatively long stroke for the suction head, thereby occupying a large space and consuming time in the bonding work. PA1 (ii) The outer leads of the devices are extremely fine so as to increase the density per unit area. This requires leads of the devices to be joined in exact alignment to the electrodes of the substrate. In order to achieve such bonding precision, it is necessary to increase the magnifying power of the camera to check the outer leads for their positional exactness because the devices punched from the film carrier are likely to be in disorder and cannot be joined to the substrates as they are. However, the increased magnifying power narrows the visual angle of the camera, and the decrease in the visual angle makes it difficult to monitor the devices over a wide range. The non-alignment of the devices is fatal to the outer lead bonding. When the devices are placed on trays, the non-alignment is particularly large. PA1 (iii) Kinds of film carriers vary from device to device, and they are wound on separate reels or placed on separate trays. However, the above-described prior art apparatus cannot mount different types of devices on a substrate at one time, but a number of apparatus must be employed corresponding to that of devices or the reels, suction head, cutting tools, etc. must be changed with every different kind of device.